It's so good that you've taken this time to open up to us. I'll do my best for advice, but regardless, I hope you feel like you can reply back even just to express yourself more. I (and your other friends here: DemonB, Sore, and Geoff) are here for you and care about what you have to say, and want you to express how you feel, in a safe space like this.
Getting onto it: the negative affection in your life likely fosters an environment which promotes stress, anxiety, and more-so depression. My perspective is that, and as our friends have also said, that the treatment from a GP, or psychologist, is difficult to act on and fulfill in such an environment. Practicing positive thought responses, and rehearsing emotionally-resolute behaviour is incredibly difficult in a place that makes you feel pressured, not cared for, and helpless.
In the long-term, I think the environment has to change. However in the short-term, hopefully a psychologist will be able to understand that the place you come from, and return to, is a hindrance on mental health recovery. Frequent sessions, and small steps, then, might be the short-term goal. Sometimes when we're in a bad place, we imagine the solution to be that we are suddenly the opposite of who were are, and that opposite person can cope. This leads us to thinking that we must be cured to be able to respond, and cope with what is keeping us down. It also places a huge burden of needing to recover quickly, as our problems don't go away.
However, our health, like the problems in our environment, don't go away immediately. Progress will be found step by step, and as we find progression (which is sometimes challenging, but at others great relief), this burden lessens, and coping becomes a much more real possibility for who we are right now.
I believe very strongly that the person you are now, is the person that will overcome your health issues. We're here to support you (although I strongly recommend a psychologist who understands this too).
Hope to hear from you soon Kate.